Tension adjustment for folding canvas cots



Sept. 30, 1952 5. HACKER TENSION ADJUSTMENT FOR FOLDINGCANVAS COTS Filed Sept. 27. 1949 4 Patented, Sept. 30, 1952 TENSION "ADJUSTMENT-FOR FOLDING I GANVAS co'rs S tanleyQBacker, Primes, Pa

Application September 27, 1949, Serial No. 118,002 re n-ms; (01. -117) (Granted underFJthe aQt of" March 3; 1883', as

The inventiondescribed herein, if. patented, may be manufactured and used by orfor the Government for governmental purposes without the payment to me'oi any royalty thereon. s

This invention relates to improvementsin folding canvas cots andinflgeneral aims. to provide a simple but effective construction permitting an adjustment in the tension of the canvas strip which supports the body of the user of the cot.

Army cots consist of a'folding wooden frame with legs, and a canvas strip secured along four sides to the frame. Thiscanvas strip may be removed from the frame and'washe'd' and then may be putv in use again; Different strips are subjected to different stressesi-mposed by heavy orlight men and some strips will sag considerably in the middle, which gives rise to-discomfort. It is highly desirable to provide a construction which will take up some ofthe sag in a canvas strip or which will permit the strip to be ad- 9 extend through each cut-away.endiportionat right angles to provide mortises.- The ends of the side members have tenons. I'llto fit the mortises 9. 7 Each end stick is. thrust through a hem H in the end of the canvas strip prior to being? united to the frame by the: mortise and. tenon. joints just described.

When the end sticks are-so arrangedlthatthecut a'way portions 8' areon the outside, as shown in Fig. 1, the canvas is subjected'to-the.greatest. tension, or in other words, thesagtake-up is then at a" maximum. If both endisticks areturncd abcuttheir' longitudinal axes through 180 the cut-away portions 8"will".be on the inside as shown in Fig. 2, which brings each end. stick one-half inch nearer the opposite. end stick;.or-

justed lengthwise when assembling it on the frame. Such a construction is provided by the present invention.

Referring to the accompanying drawings forming a part of this specification- Fig. '1 is a top plan view of the improved cot shown adjusted for maximum tension or sag take-up;

Fig. 2 is a similar view showing the parts adjusted for minimum sag take-up;

Fig. 3 is a top plan view of one of the end sticks for adjusting the tension or sag of the canvas; and

Fig. 4 is a side elevation of the end stick of Fig. 3.

a total approach Grumman; If one end; stick is arranged as in Fig. 1. while. the. otherv is=ar.- ranged as 'in'Fig. 2, there will "be a tension or sag adjustment of one-half inch. Thus provision is made for tensioning or slackening the canvas by separation or approach of its end supports in increments of one-half inch.

While the preferred form of the invention has been described in detail, it will be obvious that certain changes from the described form may be made without departing from the invention.

As shown, the cot comprises a folding frame 5 having legs (not illustrated), said frame consisting principally of wooden side members and two wooden end sticks at opposite ends of the side members. A canvas or other fabric strip 6 is stretched over the frame with hems securing it to the frame in the usual manner. Most of the details of construction of the cot are entirely conventional and hence are omitted from the drawings.

Forming part of the frame, but separable therefrom, are a pair of end sticks 1. Each end stick is a straight wooden stick, substantially rectangular in cross section, with each end cut away on one side only as indicated at 8 to provide an end portion of reduced cross section having a longitudinally extending flat surface adapted to abut the extremities of the side members. Preferably the thickness of each end portion is re-. duced one-half inch by each cut-away 8. Bores Thus instead of mortise and tenon joints to connect the end sticks with the side members of the frame, clamps might be employed. though at increased cost. The important thing is that the end sticks be cut away on one side only to be asymmetrical at their ends, to bring one side face 8 or the opposite side face into abutment with the ends of the side members of the frame, thereby to increase or decrease the distance separating the longitudinal axes of the end sticks,

which determines the tension that is imposedon the canvas strip.

It is clear that the described construction is extremely simple, is inexpensive and is fool-proof. There is nothing which will break or get out of order. No attachments to the cot are used nor is the cot modified in any way except for the provision of the cut-aways and bores.

Having described my invention, what I claim 1. A cot having a frame, including side mem- -bers and end sticks, a flexible fabric stretched one side only and lying outside the hem, bores providing mortises extending through each end portion of each end stick from the cut-away side to the opposite side of the end stick, the side members having tenons on their ends fitting said mortises when the cot is assembled, the cut-away portions providing tension adjustment means or sag take-ups according to the positions of the cut-aways relative to the tenons on the side members.

2.'In combination with a cot frame including side members and end sticks and a flexible fabric stretched over and secured to the frame, a tenon on each end of the side members, a pair of end sticks each having mcrtises extending laterally through the end sticks, for receiving said tenons, means to connect the flexible fabric loosely with the end sticks so that the end sticks may be turned on their longitudinal axes while still connected with the flexible fabric, each end stick being of reduced cross section at and near the mortises and the reduction in cross section being asymmetrical relative to the longitudinal axis of the end stick, so that the end sticks may tighten or loosen the fabric according to which ends of the mortises are presented to'the tenons.

3. A cot having a frame composed of side members and end sticks extending transversely be-' tween the side members at the ends thereof, said end sticks being positioned with the ends of their sides in abutting relation to the ends of the side members, a fabric mounted on the frame, hems formed on the ends of the fabric and enveloping the mid-portions of the end sticks, at least one of said end sticks being reversible on its longitudinal axis and formed with two opposed lonitudinal surfaces intermediate its ends which may cooperate selectively with the extremity of the enveloping hem, the end portions of said stick having opposedbearing surfaces for selectively cooperating with the adjacent ends of the 4 side members, the bearing portions of one surface of the stick being spaced a greater distance from the median line of the stick than those on the opposed surface thereof.

4. A cot having a frame comprising side members and end sticks, means securing the end sticks removably to the ends of the side members at opposite ends of the side members, at least one of said end sticksbeing reversible on its longitudinal axis and having pairs of bearing surfaces, a pair of bearing surfaces on one side of said end stick being spaced a greater distance from the longitudinal axis of the end stick than the-pair of bearing surfaces on the other side of said end stick, a flexible fabric loosely secured to and adapted to be stretched between the side members so as to be held thereby yet be capable of longitudinal movement thereon, said fabric having a hem at least one end enveloping loosely the mid portion of the reversible end stick, so that said end stick may be reversed inside the envelcping hem to bring opposite sides into contact with the ends of the side members, thereby to displace the'mid portion of said end stick in a direction parallel to the longitudinal axis of the frame so as to stretch or relax the tension of the fabric on the frame.

STANLEY BACKER.

REFERENCES CITED The fcllowing references are of record in the file of this patent:

UNITED STATES PATENTS 

